There is known a parking assistance device configured to assist a parking operation in which a vehicle is parked by traveling in reverse from a reverse start position toward a target parking position (see Japanese Patent Application Publication No. 2011-001029). In Japanese Patent Application Publication No. 2011-001029, the parking assistance is performed while avoiding avoidance points set around the target parking position.
However, the parking assistance device described in Japanese Patent Application Publication No. 2011-001029 focuses only on avoiding collision in the route along which the vehicle travels in reverse from the reverse start position toward the target parking position. Accordingly, when the width of a vehicle passage which a parkable area faces is small, the vehicle will interfere with an obstacle at the reverse start position. Thus, the parking assistance can be performed only in limited situations.